Conventionally, known airships fly using a proper propelling means thereof while generating a lifting force using a ship-floating gas. Airships are classified into large ones capable of accommodating persons and crewless ones. For crewless airships, airship systems are known in which a movable radio station is prepared on the ground and the airship is piloted by manipulations of an operator in the movable radio station. In this case, the operator controls the moving direction of the airship by sending a navigation instruction to the airship by radio and operating the propelling means of the airship accordingly.
On the other hand, Japanese Patent Laid-Open No. 6-247393 discloses an airship system in which the airship is controlled according to a navigation program input to a computer in advance. In this airship system, an airship is provided with a controller including a CPU and the controller controls a route of the airship according to the navigation program. When sensors that are provided at top and bottom positions, front and rear positions, and left and right positions of the air ship detect an obstacle, an operation to avoid the obstacle is performed.
However, in the above-described conventional airship systems with piloting by an operator, it is necessary that the operator pilot the airship all the time. Therefore, an accident may occur unless the operator has a superior piloting technique. There is another problem that those airship systems are not suitable for long-time flights.
On the other hand, the method disclosed in the above publication requires no operators and enables long-time flights. However, since the airship itself is mounted with a complex controller and a lot of sensors, the load weight is heavy and much power is consumed: the airship needs to be increased in size to obtain a sufficient lifting force. Therefore, this system has a problem that it cannot be used for controlling a small airship.
The present invention has been made to solve the above problems, and an object of the invention is therefore to provide an airship system capable of dispensing with piloting by an operator and reducing the load weight and the power consumption of devices that are mounted on the airship.